The prior art already has many examples of track joints for use in tracks for crawler tractors, and these joints commonly include the elements of a track pin and a bushing thereon and two track links presenting a space therebetween with some type of dirt seal disposed in the space to keep the joint free of dirt. One general example of prior art is found in my U.S. Pat. No. 3,948,574.
In the prior art track joints, it is common practice to have a thrust member interposed between the two track links which are piloted on a track pin, or between a track link and a bushing piloted on the track pin. Examples of this type of construction are found in U.S. Pat. No. 3,376,081 and 3,544,588 and 3,841,718. In these examples, the thrust bearing surface of the thrust member or ring is substantially less than the end or projected area of the bushing piloted on the pin, and thus the small area of the thrust ring bears against the link and the bushing to create undesirable high pressure and consequent wear at those locations. U.S. Pat. No. 3,347,602 shows still another example of the prior art arrangement of a small area of thrust contact between the bushing and the link, and thus there is the undesirable wear at that location.
That is, it will be understood that the track joint is an articular joint which has the links pivot relative to each other, and of course there must be bearing surfaces intermediate the links to thus maintain the links in their positions and to present a secure and firm and dirt-sealed type of joint. However, as mentioned above, the prior art fails to arrange a track joint wherein the force of the thrust between the pivotal joint members is distributed over a sufficiently large area to avoid a highly pressurized or localized area of force, and thus the prior art has the track joint vulnerable to wear and failure with regard to its mechanical and dirt-sealing intentions.
Accordingly, the present invention provides a track joint which is mechanically reliable and which performs the dirt-sealing functions, and, more specifically, the track joint of this invention provides a low mechanical pressure between the pivotal parts of the joint and relative to the thrust forces inherent in the joint.
Still further, another objective and advantage of this invention is to overcome the aforementioned deficiencies of the prior art and to accomplish the aforementioned objectives and to do so with a track joint arranged with a thrust member which transmits only a low mechanical pressure between the elements of the joint, and with the joint having a dirt-sealing effect, accomplished by both the thrust member and an elastic dirt-sealed member, to thereby retain the joint in a dirt-free condition.
Still further, it is an object and advantage of this invention to provide a track joint which accomplishes the aforementioned and which does so with a minimum of parts and with no complex but only relatively inexpensive and easily provided and maintained parts, and with the entire joint being sturdy and reliable and dirt-free and one of long life due to the low pressure of the mechanical forces acting within the joint.